Answer:
Each element has unique physical properties such as density, melting point, boiling point, etc. These properties can be used to identify an element using a reference book that contains such information about each element. Flame tests, atomic spectra, and spectroscopy can be used to identify some elements.
Explanation:
Dont know the first one but
2.particles
3. waves/energy
4.radio/air
5.eardrumbs
6.faster/particles
7.slower/